Controlling your World the Easy Way

ddm novastar LE-40V

ddm novastar LE-40V

Posted: Mon Jul 14, 2014 9:11 pm

by honestann

Greetings,

I am a long time developer of electronics devices and products, but have been busy writing software for several years while SMT has taken over the world of electronics. Now I want to make a series of new devices and products, but... virtually all components I want to adopt are SMT.

I used to layout my own PCBs with tape (aarg) and assemble my PCBs manually on my workbench, but that no longer flies!

I have successfully switched to software for schematic capture and PCB layout, but the components on my PCBs are simply too small to assemble manually (even under stereo microscopes). The reason isn't as much component size (given the microscope), but instead the inability to place components accurately. In theory it should be possible, but static cling between tweezers or even vacuum tip devices and components means the components shift when they are released and the tip moves away.

So I'm stuck. No way to continue without buying stencil printer, pick-and-place machine, and reflow oven.

After many months of research I settled on the exact same pick and place you purchased... the ddm novastar LE-40V. I also chose their new high-end automatic stencil printer SPR45VA because I've heard solder paste problems are the biggest cause of problems for many people... plus my designs require 0201 discretes, 0.40mm pitch QFN, and 0.50mm pitch BGA (and perhaps 0.30mm or 0.35mm pitch in 1 or 2 years). I also chose their GF12-HT or GF120-HT reflow oven to support these small components and lead-free solder (if necessary).

I am close to deciding to purchase, but recently one fellow who does PCB assembly keeps telling me horror stories about how every PCB will not work due to improperly placed components, bad solder joints, etc. But he is working with a 10 year old machine that he purchased used, so I am a bit skeptical that his claims apply to all brands of SMT lines and new equipment (though I don't doubt his experiences are what he says).

Since you have the same equipment I plan to buy, I want to ask you what experiences I should expect? And if you are willing, I would love to come to your lab, garage or basement and watch you assemble some PCBs so I can experience the whole process for myself. Nothing I design is even remotely competitive with your products, so you need not worry about that! And yes, I am just an individual, not a company.

To help you understand the kind of PCBs I design, I post a couple links below that you can click on to view images of the two PCBs in a "robotics vision" subsystem I designed.

Note: the vias in the pads under the BGA solder balls have been filled with conductive material, and coated/overlayed with copper (as part of the PCB manufacture process). In other words, there are no vias under the BGA balls any more, so the BGA solder balls will not flow into the vias and cause problems.

Otherwise the PCB designs are fairly conventional. The trace/space is 0.004" minimum, the smallest caps are 0201 (usually between BGA pads, but also elsewhere), etc. The smaller ice_eye PCB is a 6-layer PCB. The larger ice_quad PCB is an 8-layer PCB. The inner layers are mostly ground and power planes, but a small quantity of traces are run on one inner layer (not that this should matter to assembly).

The PCBs do have a few through-hole components too, but I figure those would be installed and soldered manually. For example, the following are through-hole components: large electrolytic capacitor, power-in-jack, microphone-in-jack, headphone-out-jack, RJ45 jack for gigabit ethernet, linear array of LEDs, and quite a few conventional ribbon cable headers (26-pin, 40-pin, etc).

In case you wonder, I tell you what this device is. The "ice_quad" PCB is a "camera controller" that connects to a PC via the RJ45 gigabit ethernet connection. Up to 4 of the "ice_eye" PCBs (in cases of course) connect to the "ice_quad" controller. Each "ice_eye" is a 2592x1944 pixel digital video-or-still camera.

You can probably imagine the obvious applications for a 1 to 4 camera system like this. The most obvious is a security camera with 4 cameras that point in 4 directions and feed video (or still) images to the PC on command. The PC can control each camera separately, so they can run at different frame rates, different resolutions, different sub-window positions and sizes, etc.

Another obvious application is "motion capture". Stick some colored [retroreflective] dots on an object or human, position the 4 cameras at ceiling level in the 4 corners of a room (or area of the room), and point them all towards a central area. Now the object or person can move around and the video images will be sent to the PC, which can collect and record precision motion capture information.

My next projects is a super-high speed/resolution camera (roughly 8K x 5K pixels @ 300 frames per second). That will involve even faster signals (much faster in fact, either 2.50Gbps or 3.125Gbps differential signals). That product needs to be absolutely as compact as possible, so the push towards smaller components will continue to be very strong.

I look forward to your reply, either here or via my email address (which I assume you have via the forum signup process).

Re: ddm novastar LE-40V

Posted: Tue Jul 15, 2014 7:17 pm

by Daniel

You must have a few gray hairs by now since I have many and I only laid out a few boards with tape on a light box. I've been using OrCAD since v1.2 and the first PCB program I used was Tango. I gave up on it pretty soon and switched to Pads. For an entry system I now recommend people use Diptrace and I see from the files you posted that you use it.

Using modern components on old equipment is a recipe for frustration and horror stories. I don't see any reason why your boards can't be assembled on the equipment you listed. You will have a learning curve though because Pick and Place machines are not as simple as they may appear at first glance. Even things like threading the tapes through the feeders takes a bit of practice to get it right, specially Digireels or Mousereels that have splices in them. Then getting the tension right on the take up reel for the cover tape also takes a bit of practice. I thought I had mine perfectly set up and then found the tension a bit low as the take up reel got full. Another fun thing is learning how to remove a tape from a reel without scattering components all over the workplace and into the innards of the machine.

Before dropping a bunch of money on a set of equipment I sincerely suggest that you visit the manufacturer for a few days and see the machines in action. In a few months Novastar has an open house where they will demonstrate all their equipment and it would be good if you visited them.

In terms of equipment, I still think the LE40 is great value for money and it works really well. It is wonderfully accurate and the software is very good, second only to the MyData machines which cost more than $100k. Spending money on a good stencil printer is a really good idea. You live and die by the quality of the solder paste deposit on your PCB. Almost all my assembly problems trace back to solder paste issues and a few to the temperature profile in the oven. I have very few issues relating to the placement of the parts. There are a few components which are problem children; I designed a pot into one of my boards. I haven't used a pot in more than 10 years, I dislike 'tweaking' things. The first pot I chose wouldn't pick properly. The manufacturer chose to put a 3x3.5mm pot in an 8mm tape and there simply isn't enough room to clear the edge of the feeder. I just switched to another brand of pot. Another thing I learned is to avoid lead free HASL as a board finish for surface mount. I now use ENIG exclusively. Lead free HASL is not particularly flat but that is not nearly as important as the fact that it oxidizes during storage leading to solder issues. ENIG is flat and it solders really well even after extended storage.

Regarding the person with the horror stories of assembly problems I have this to say; Cell phones are assembled in the millions per day with really tiny components like 01005 with perfect yield (no rework) and tiny 0.4mm BGA parts that dissipate 1.5W of power without heatsinks. Assemblies similar to that is done every single day in Si Valley on much lower cost equipment than used in the phone factories with great results. Knowledge is an important part of the process and skimping on the wrong part of the process will drive you nuts.

Everything electronic is headed towards surface mount technology so learning how SMT assembly works is essential.

Re: ddm novastar LE-40V

Posted: Tue Jul 15, 2014 9:25 pm

by honestann

Thanks for your comments. Yeah, I started finding platinum blonde hairs not that long ago. But no grey ones! Yuck, yuck! Hahaha.

Yes, I chose diptrace after much reading and research. After a week or so of learning curve, found their schematic capture and PCB layout to be effective and efficient... and reasonably priced (and with 30-days free to make sure). However, since diptrace was my first purchase, and the only package I've ever operated, I can't be sure it is the best. But I'm happy and don't want to learn new tricks unless I must.

Since you know diptrace, tell me this. How do you convert the output of diptrace into inputs to your LE40V machine? How much information do you need to add to what is imported from diptrace? In my case, I created the part files and package files for ALL my components. I didn't import or adopt anyone else's. That assures all my parts and packages are defined in a completely consistent manner. At first I looked at several imported parts and packages, but considered many of them to be sloppy and strange (and often simply WRONG). For example, I decided to put all my origins in the exact middle of the package, while imported files were all over the map --- even several inches outside the package!!!

Anyway, can you summarize what is involved to convert diptrace output to LE40V input?

Do manufacturers really let people show up and spend days watching the machines in action? In fact, do the manufactures actually HAVE their machines running at their factories so people can observe them in action? And where is this novastar demonstration you mentioned? One reason I asked to visit you was because you are within driving distance (albeit still quite a ways), while the novastar factory is at the other side of the universe.

Of course, I also know I'd get more objective answers from you. And you'll mention less pretty aspects of the equipment and processes than they are likely to mention (for fear of scaring me away).

I assume the LE40V has linear encoders? Is that true?

I've seen several youtube videos that show placement with other pick-and-place machines, and found the placement accuracy to be rather poor in some cases. In other cases, the placement were quite good (apparently perfect). Unfortunately, none of the videos were the LE40V or other novastar machine.

I did buy most of my components from digikey, so I probably have some digireels. OTOH, I did try to buy the full natural quantity (or some integer multiple thereof), so hopefully that means many if not most of my reels are the originals. But I'm not sure, of course. If you have suggestions to help avoid problematic component reels, please do relay them.

You know what would be better than me flying to novastar? You assemble my PCBs while I watch. That would probably be something like 20 or 25 of the larger PCB (ice_quad) and 25 to 50 of the smaller PCB (ice_eye)... though fewer of each also serves to test how much trouble an experienced assembler like you would encounter. I gather you avoid 0201 when you can! Well, maybe my PCBs are a place to experiment? If you're potentially willing to attempt this experiment, just tell me how much you want for your service and your trouble.

I'm pretty sure my PCBs are ENIG. All conductive surfaces were definitely gold plated, and your ENIG acronymn rings a bell. I think you can tell from the photos that the conductive surfaces are gold.

Also tell me... how many reels do you consider minimum for the LE40V and my kind of PCBs? I gather the 8mm feeder banks are cheaper than individual feeders, but feeders are still expensive. How many feeders did you buy, and how much did you pay for them?

Yes, I'm at a point where I need to either abandon hardware (electronics) forever (and limit myself to science, engineering and software)... or get back into hardware and crank out at least several more devices and products. I've created a great many software and hardware (and precision optical and mechanical) devices and products over the years, and my experiences with hardware products were almost always more rewarding. People (and companies) expect to pay for hardware, but too often expect software to be free, and resist paying the piper (programmer). I never manufacture the products I designed, developed and prototyped. I always just licensed or sold my designs to a company that manufactured and/or marketed similar products. I have no interest in marketing, but I enjoy developing awesome products, as difficult and troublesome as that sometimes is. Though I must admit, FPGAs might be the death of me!